Display shows E03 and the coffee maker stops heating; water remains cold or lukewarm.

Safety first: Unplug the coffee maker and let it cool for at least 30 minutes. The heating block and base plate can remain hot after use.

• Power reset: Unplug the unit for 10 minutes to clear any temporary sensor error, then plug back in and test.
• Check for moisture: Inspect the underside and sides of the machine for signs of leaks that may have dripped onto the sensor wiring. If you see moisture, dry the exterior thoroughly and do not use the unit until the source of the leak is addressed.
• Gentle tap test: With the unit unplugged and cool, gently tap the side of the base where the heater is located to dislodge any minor oxidation on connectors. Do not strike hard or use tools.
• Do not bypass safety: Never attempt to bypass the temperature sensor or thermal cut-out; this is a critical safety device to prevent overheating and fire.

If E03 reappears consistently, the NTC sensor or its wiring is likely defective and should be replaced by a service technician familiar with T-fal coffee makers.